1. Field of the Invention
This invention relates to a method for the dimerization of .alpha.-methylstyrenes. The .alpha.-methylstyrenes herein described are compounds having the following formula (I) ##SPC1##
wherein R represents hydrogen or alkyl containing from 1 to 4 carbon atoms. The dimers of .alpha.-methylstyrenes include two kinds of unsaturated dimers, that is, 2,4-diphenyl-4-methyl-1-pentenes (hereinafter referred to simply as 1-pentenes) having the general formula (II) ##SPC2##
wherein R has the same meaning as defined in formula (I) above, and 2,4-diphenyl-4-methyl-2-pentenes (hereinafter referred to simply as 2-pentenes) having the general formula (III) ##SPC3##
wherein R has the same meaning as defined in formula (I) above, and one kind of saturated dimers, that is 1,1,3-trimethyl-3-phenylindanes (hereinafter referred to simply as indanes) having the general formula (IV) ##SPC4##
wherein R has the same meaning as defined in formula (I) above. More particularly, this invention rlates to a method for the preparation of unsaturated dimers of .alpha.-methylstyrenes which contain as their main component 1-pentenes expressed by the above-mentioned formula (II).